The present invention relates generally to conveyors, and more particularly to a conveyor system having a transfer zone between the end of a first conveyor and the start of a second conveyor.
It is common in conveyor systems to have two or more conveyors that are positioned in end to end relationship that are adapted to feed articles along a feed path, such as in food processing or packaging lines. In the transfer zone where the two conveyors come together, it has always been a problem to provide an efficient passage of the articles from the feeding portion of the first conveyor to the receiving portion of the second conveyor. One of the most prevalent problems is to provide a conveyor transfer assembly for this purpose that not only provides for a smooth transition along the transfer zone, but also can be released in the event that a jam occurs. For example, a jam can occur at the transfer zone due to the lodging of a foreign object within a recess of the modular conveyor, or simply from an object that is out of place carried along by the article being conveyed. In either case, there is a problem in preventing damage to the articles and/or the conveyor in the event of this type of jam.
In the past, there have been attempts to solve this problem, but insofar as I am aware a truly acceptable solution has not been found prior to the present invention. For example, in the Chance U.S. Pat. No. 5,009,307, to et al. issued Apr. 23, 1991, there is a provision for a plate that is held in position by the frame on one end of a conveyor. In order to hold the plate in position, spring loaded detents are required at both sides. Depending on the strength of the spring for each detent, the plate is designed to be released in the event of a foreign object being lodged between the end of the conveyor and the plate. The unreliability of this type of article transfer means plays a key role in the limited acceptability that it has. For example, when the conveyor system is new, and the springs have a high compression rate, then the release of the transfer section requires a substantial force in order to be operative. On the other hand, over the years, and assuming multiple release episodes of the transfer section, the springs weaken and the surfaces of the detent are changed so that the release becomes easier. In such an event, the transfer section can literally fall out of the conveyor system of its own accord. This is especially true in an instance where the spring force is overcome when heavy articles are being conveyed.
Furthermore, in an arrangement such as shown in the '307 patent, the cost of the transfer section is unduly high. Also, there is no provision made for anti-friction transfer, such as by the inclusion of rollers. As a result, the speed of the articles being transferred must be increased in order to make certain that enough momentum remains in the articles to cause them to successfully cross the exit zone, as taught by the patent.
Accordingly, the need exists for a new type of conveyor transfer assembly for articles feeding along a feed path or transfer zone between two conveyors. A prerequisite is that the transfer assembly be simple and inexpensive to manufacture and substantially fool proof in operation. The transfer assembly should also be lightweight and supported freely on the conveyor support, preferably resting only by gravity, for easy and quick pop-up release in the event of a foreign object causing an article jam or the like.
Other arrangements prevalent in the prior art usually take the form of permanently mounted roller sections, wherein individual rollers are mounted on pairs of arms that are mechanically held in position for pivoting action. Again, this arrangement is such that the consistent avoidance of damage in the event that a jam occurs is very inconsistent. An example of this type of prior art arrangement is shown in the earlier U.S. Pat. No. 2,624,444, to Casabona issued Jan. 6, 1953. Thus, this line of technology also indicates that improvement is necessary to allow for a freer and more predictable release of the conveyor transfer section in the event of an article jam or the like.